Some digital printing systems and processes, for example, inkjet printing systems and processes introduce significant moisture content during operation, particularly when the system is used to print multiple colors on a print media. Due to its moisture content, the print media expands and contracts in a non-isotropic manner often with significant hysteresis. The continual change of dimensional characteristics of the print media often adversely affects image quality. Although drying is used to remove moisture from the print media, drying too frequently, for example, after printing each color, also causes changes in the dimensional characteristics of the print media that often adversely affects image quality.
During an inkjet printing process, as the print media absorbs the water-based inks applied to it, the print media desires to expand. When the direction of expansion is in a direction that is perpendicular to the direction of media travel, it is often referred to as expansion in the cross-track direction. For example, when the print media wraps around a roller of an inkjet printing system, the outer, typically unprinted, edges of the print media remain attached to the roller although the remaining typically printed portions of the print media expand outwardly. The outward expansion, commonly referred to as buckling, of the print media in the cross-track direction between the firmly attached outer edges of the print media creates lengthwise ripples or wrinkles in the print media. Wrinkling of the print media during the printing process often leads to permanent creases forming in the print media which ultimately affects image quality.
As such, there is an ongoing need to provide digital printing systems and processes with the ability to effectively handle print media expansion associated with the absorption of water by the print media.